Discharge		Type of square law
Lumen		Filaments are made from this metal
Envelope		Flow of light radiated fron a single source
Monochromatic		Radiation given off by mercury lamps
Electromagnetic		Light consisting entirely of one wavelength
Sodium		Measurement of power
Halogen		Takes into account deterioration of reflecting surface and light output
MaintenanceFactor		Light is this type of radiation
Mercury		Measure of the brightness of the light reflected from a surface
Glow		Name given to the outer glass vessel of lamp
Efficacy		Lamp output compared to energy input
Prism		These types of lamps do not rely on the heating of a filament to produce light
Flourescent		Provides the starting voltage and current control
Capacitor		Lamp will not restrike if mains fails until this has reduced through cooling
Pressure		Gas contained in some types of filament lamps
Ultraviolet		Type of discharge lamp
Tungsten		Device which splits light into seven colours
Luminance		The ability of the lamp to show colours faithfully
ColourRendering		Name of filament in discharge lamps
Cathode		Device used in discharge lamp circuits to improve power factor
Watts		Type of lamp often used for street lighting
Choke		Type of vapour contained in flourescent lamps
Inverse		Type of starter used in flourescent lamp circuits